The conventional approach to making multichip circuits provides a printed wiring board (PWB) having a desired pattern of metal interconnects and mounting the integrated circuits (typically in packages with metal leads) in appropriately patterned locations on the board. In addition to the interconnections, PWBs also permit the use of additional discrete components that are necessary for the circuits, such as discrete resistors, capacitors and transistors.
This conventional approach worked well with digital circuits which generally required little more than a pattern of conductive leads interconnecting several digital chips. It does not, however, work well with analog and mixed-signal circuits which often require active components in the interconnection paths. Chips can be custom designed to provide the desired active components, but this custom design is expensive and fails to fully exploit the economies of scale available through the use of commodity chips. Thus fabrication of such circuits using PWB technology typically involves the expensive and area-consuming process of applying numerous discrete components in addition to the ICs. Accordingly, there is a need for an improved method for making multichip circuits.